Drug delivery inhaler devices

ABSTRACT

An adapter for fitting to a drug delivery device, the adapter including: an outlet for communication with the mouth of a patient; an air flow path through the adapter along which air is drawn to the outlet by inhalation by the patient; an inlet adapted for connection to a mouthpiece of the drug delivery device; and an air flow rate indicator operable to indicate when the air flow rate along the air flow path is at or above a predetermined minimum level suitable for delivery of the drug to the patient. A drug delivery device having, in its body, an air flow rate indicator operable to indicate when the air flow rate along the air flow path is at or above a predetermined minimum level suitable for delivery of the drug to the patient.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/749,203, filed Jan. 24, 2013, now U.S. Pat. No. 9,427,534, which isentitled “DRUG DELIVERY INHALER DEVICES”, which application isincorporated herein by reference in its entirety.

BACKGROUND TO THE INVENTION

Field of the Invention

The present invention relates to drug delivery inhaler devices, such aspressurised metered dose inhaler (pMDI) devices and dry powder inhaler(DPI) devices and adapters for fitting to such drug delivery inhalerdevices. The invention also relates to methods of operation of suchdevices and adapters. Of particular interest in this invention is theprovision of means for improving patient compliance with such devices.

Related Art

GB-A-2372704 discloses a device, such as a spirometer, for determiningthe respiratory flow rate of a patient. The device includes two reedsadapted to generate an audible signal at different air flow speedsthrough the device. The first reed generates an audible signal of afirst pitch when the air flow reaches a predetermined minimum. Thesecond reed generates an audible signal of a second pitch when the airflow reaches a predetermined maximum. Thus, the patient is informed whenthe air flow is within a desirable range, between the predeterminedminimum and maximum.

Lavorini et al (2010) [F. Lavorini, M. L. Levy, C. Corrigan and GrahamCrompton, “The ADMIT series—issues in inhalation therapy. 6) Trainingtools for inhalation devices” Primary Care Respiratory Journal (2010)19(4) 335-341] set out a review of training tools for inhalationdevices, including the device disclosed in GB-A-2372704, referred to asthe “2Tone” trainer. Such a trainer is intended to be used only as atraining device and never itself as a drug delivery device.

Lavorini et al (2010) comment that two of the most critical patienterrors in the uses of pMDI devices are a failure to coordinateinhalation with actuation of the device and inhaling the aerosolizeddrug too quickly. The full potential of the drug then cannot berealised.

Lavorini et al (2010) review various other inhaler training devices ofdifferent degrees of sophistication. However, each of these devices is atraining device, in the sense that a patient uses the training device inorder to “learn” an optimum method of using a drug delivery inhalerdevice. For the simplest devices, once the patient is deemed to havelearned the correct technique, the training ends, but there is noongoing check on whether the patient continues to use the correcttechnique, over time, with their prescribed drug delivery inhalerdevice.

Corrigan (2011) [C. J. Corrigan “Asthma therapy: there are guideline,and then there is real life . . . ” Primary Care Respiratory Journal(2011) 20(1) 13-14] and Hardwell et al (2011) [A. Hardwell, V. Barber,T. Hargadon, E. McKnight, J. Holmes and M. L. Levy “Technique trainingdoes not improve the ability of most patients to use pressurisedmetered-dose inhalers (pMDIs)” Primary Care Respiratory Journal (2011)20(1) 92-96] report on tests of patient compliance using pMDI devices.The tests took place during April-June 2008. The commentary in Corrigan(2011) on the results reported by Hardwell (2011) discusses the factthat 85.6% of 1291 patients tested failed their first assessment ofwhether they were able to use their pMDI device correctly. This isconsidered to be a critical issue—incorrect use of a pMDI device basedon this assessment means that the drug delivered to the patient is beingdelivered sub-optimally. In turn, this means that the patient does notreceive the correct dose of the drug, which can lead to serious problemsin the ongoing treatment of conditions such as asthma. It is consideredthat such problems remain even when patients have in the past receivedsome training on the correct technique to adopt for using theirprescribed drug delivery inhaler device.

SUMMARY OF THE INVENTION

The present invention has been devised in order to address at least oneof the above problems. Preferably, the present invention reduces,ameliorates, avoids or overcomes at least one of the above problems.

Accordingly, in a first aspect, the present invention provides anadapter for fitting to a drug delivery device, said adapter comprising:

-   -   an outlet for communication with the mouth of a patient;    -   an air flow path through the adapter along which air is drawn to        the outlet by inhalation by the patient;    -   an inlet adapted for connection to a mouthpiece of said drug        delivery device; and    -   an air flow rate indicator operable to indicate when the air        flow rate along the air flow path is at or above a predetermined        minimum level suitable for delivery of the drug to the patient.

In a second aspect, the present invention provides a use of a drugdelivery inhaler device to deliver a drug to a patient by inhalation,the method comprising:

-   -   connecting the inlet of an adapter according to the first aspect        to the mouthpiece of the drug delivery device;    -   the patient inhaling through the outlet of the adapter and        thereby establishing an air flow along the air flow path through        the adapter and device;    -   the air flow rate indicator in the adapter providing an        indication to the patient when the air flow rate along the air        flow path is at or above a predetermined minimum level suitable        for delivery of the drug to the patient; and    -   while the air flow rate indicator provides said indication,        operating a drug reservoir seated in the device to deliver a        dose of aerosolized drug into the air flow path in the device        for inhalation by the patient at the adapter outlet.

In a third aspect, the present invention provides a medicament fortreatment of asthma and/or chronic obstructive pulmonary disease (COPD)in a patient, the medicament delivered to the patient by inhalationusing a drug delivery inhaler device by the steps:

-   -   connecting the inlet of an adapter according to the first aspect        to the mouthpiece of the drug delivery device;    -   the patient inhaling through the outlet of the adapter and        thereby establishing an air flow along an air flow path through        the adapter and device;    -   an air flow rate indicator in the adapter providing an        indication to the patient when the air flow rate along the air        flow path is at or above a predetermined minimum level suitable        for delivery of the drug to the patient; and    -   while the air flow rate indicator provides said indication,        operating a drug reservoir seated in the device to deliver a        dose of aerosolized drug into the air flow path in the device        for inhalation by the patient.

In this aspect the medicament is preferably one or more selected fromthe group consisting of: bronchodilators such as β₂-adrenoceptoragonists (e.g. salbutamol, terbutaline, salmeterol, formoterol) andanticholinergics (e.g. ipratropium bromide, tiotropium); glucocorticoids(e.g. prednisolone, fluticasone, budesonide, mometasone,beclomethasone); theophylline; phosphodiesterase-4 antagonists (e.g.roflumilast, cilomilast); tumor necrosis factor antagonists (e.g.infliximab); leukotriene antagonists (e.g. zafirlukast); mast cellstabilizers (e.g. cromolyn sodium).

Accordingly, in a fourth preferred aspect, the present inventionprovides a drug delivery inhaler device having:

-   -   an outlet for communication with the mouth of a patient;    -   an air flow path through the device along which air is drawn to        the outlet by inhalation by the patient;    -   a seat for location of a drug reservoir, the drug reservoir        being operable to deliver a dose of aerosolized drug into the        air flow path for inhalation by the patient; and    -   an air flow rate indicator operable to indicate when the air        flow rate along the air flow path is at or above a predetermined        minimum level suitable for delivery of the drug to the patient.

In a fifth preferred aspect, the present invention provides a use of adrug delivery inhaler device to deliver a drug to a patient byinhalation, the method comprising:

-   -   the patient inhaling through an outlet of the device and thereby        establishing an air flow along an air flow path through the        device;    -   an air flow rate indicator providing an indication to the        patient when the air flow rate along the air flow path is at or        above a predetermined minimum level suitable for delivery of the        drug to the patient; and    -   while the air flow rate indicator provides said indication,        operating a drug reservoir seated in the device to deliver a        dose of aerosolized drug into the air flow path for inhalation        by the patient.

In a sixth preferred aspect, the present invention provides a medicamentfor treatment of asthma and/or chronic obstructive pulmonary disease(COPD) in a patient, the medicament delivered to the patient byinhalation using a drug delivery inhaler device by the steps:

-   -   the patient inhaling through an outlet of the device and thereby        establishing an air flow along an air flow path through the        device;    -   an air flow rate indicator providing an indication to the        patient when the air flow rate along the air flow path is at or        above a predetermined minimum level suitable for delivery of the        drug to the patient; and    -   while the air flow rate indicator provides said indication,        operating a drug reservoir seated in the device to deliver a        dose of aerosolized drug into the air flow path for inhalation        by the patient.

In this aspect, the medicament is preferably one or more selected fromthe group consisting of: bronchodilators such as β₂-adrenoceptoragonists (e.g. salbutamol, terbutaline, salmeterol, formoterol) andanticholinergics (e.g. ipratropium bromide, tiotropium); glucocorticoids(e.g. prednisolone, fluticasone, budesonide, mometasone,beclomethasone); theophylline; phosphodiesterase-4 antagonists (e.g.roflumilast, cilomilast); tumor necrosis factor antagonists (e.g.infliximab); leukotriene antagonists (e.g. zafirlukast); mast cellstabilizers (e.g. cromolyn sodium).

All aspects of the invention may have any one or, to the extent thatthey are compatible, any combination of the following optional features.

Preferably, the adapter in the first, second and third aspects is asubstantially cylindrical tube (i.e. having a substantially constantcross-sectional area) unlike typical inhaler spacers. Preferably, theoutlet of the adapter is adapted for connection to the mouthpiece of adrug delivery device by the inclusion of a press-fitting connection. Thepress/push-fitting connection is adapted to form an interference fitwith the outlet/mouthpiece of the drug delivery device. The outlet ofthe adapter is adapted to form an air-tight seal upon connection withthe mouthpiece/outlet of the drug delivery device.

Preferably, the drug delivery inhaler device is a pressurised metereddose inhaler (pMDI) device. In such devices, the drug is typicallyprovided in the form of a liquid held in a pressurised canister.Actuation of the canister is typically achieved by depressing thecanister towards the body of the device. This causes an interactionbetween the canister and the seat that causes a metered dose of liquidto be ejected from the canister, along with a propellant gas. The liquidis aerosolized in the device, for inhalation by the patient. A drug ofparticular interest is salbutamol, marketed under the trade namesVentolin™, Aerolin™, Ventorlin™, Asthalin™ Asthavent™, Proventil™ andProAir™, for the management of asthma.

Pressurised metered dose inhaler (pMDI) devices typically have a bodyportion substantially in an L-shape, with the upright of the L having aninlet adapted to receive the drug reservoir and the transverse of the Lproviding an outlet (mouthpiece) for communication with the mouth of thepatient.

Preferably, the predetermined minimum air flow rate through the deviceis at least 30 liters per minute. Preferably, the predetermined minimumair flow rate through the device is at most 60 liters per minute. Aswill be appreciated, the preferred range of air flow through the devicein order to ensure satisfactory delivery of the drug to the patient is30-60 liters per minute. A slower air flow rate risks that the aerosolparticles will settle before being delivered to the required anatomy ofthe patient (typically to the bronchial tubes, and/or deeper into thelungs). A higher air flow rate risks the aerosol particles simplyhitting and adhering to the back of the patient's throat, withoutpenetrating deeper into the patient's pulmonary system.

In the fourth to sixth aspects, the air flow rate indicator may beprovided in a body portion of the inhaler. This is advantageous, sinceit allows the indicator to be formed integrally with the body portion ofthe inhaler, and thus need not increase the overall size of the inhaler.

In the first, second and third aspects, the air flow rate indicator isprovided in the adapter. This is advantageous in that, although the useof such an adapter increases the overall size of the device when in use,it allows a suitable air flow rate indicator to be retrofitted to anexisting inhaler. The adapter may increase the distance between the drugreservoir and the mouth of the patient.

The air flow path through the device can be considered in two sections,relative to a drug injection/ejection point in the air flow path atwhich point the drug reservoir ejects drug into the air flow. An inletregion of the air flow path is typically located upstream of the druginjection point and leads to the air inlet of the device. An outletregion is typically located downstream of the drug injection point andleads to the outlet (mouthpiece) of the device. In the fourth to sixthaspects, the air flow rate indicator may be provided in the inlet regionof the air flow path i.e. upstream of the point at which the drug isejected from the reservoir into the air flow path. For example, the airflow rate indicator may be provided adjacent the drug reservoir.Alternatively, the air flow rate indicator may be provided in the outletregion of the device i.e. downstream of the point at which the drug isejected from the reservoir into the air flow path.

In some embodiments of the first to sixth aspects, the air flow rateindicator generates an audible signal. For example, the air flow rateindicator may be a pressure-driven mechanical oscillator, such as areed. Alternatively, the air flow rate indicator may be a whistle.

In some embodiments of the first to sixth aspects, the air flow rateindicator generates a visual signal. For example, air flow rateindicator may have a mechanically-operated signal such as a vanemoveable in response to a pressure difference across it. In preferredembodiments, of the fourth to sixth aspects, the air flow rate indicatoris adapted to generate a visual signal and is provided at the air inletof the drug delivery device.

In some embodiments of the first to sixth aspects, the air flow rateindicator may operate electronically. Electronic air flow rate sensorsare known, e.g. based on Venturi sensors. In the case of an electronicair flow rate indicator, the patient may be alerted to the air flow rateby a suitable signal such as an audible signal, a visual signal, or acombination of audible and visual signals. The audible and/or visualsignal may be generated electronically.

Further optional features of the invention are set out below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of examplewith reference to the accompanying drawings in which:

FIGS. 1-3 show various schematic views of an adapter according to thefirst aspect of the invention;

FIGS. 4-6 show various schematic views of a pMDI device according to anembodiment of the fourth aspect of the invention;

FIGS. 7-9 show various schematic views of a pMDI device according toanother embodiment of the fourth aspect of the invention; and

FIGS. 10-12 show various schematic views of a pMDI device according to afurther embodiment of the fourth aspect of the invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS, AND FURTHER OPTIONALFEATURES OF THE INVENTION

Pressurised metered dose inhaler (pMDI) devices typically have a bodyportion substantially in an L-shape, with the upright of the L adaptedto receive a drug reservoir and the transverse of the L providing anoutlet for communication with the mouth of the patient.

The drug is typically provided in the form of a liquid held in apressurised canister. Actuation of the canister is typically achieved bydepressing the canister towards the body of the device. This causes aninteraction between the canister and the seat that causes a metered doseof liquid to be ejected from the canister, along with a propellant gas.The liquid is aerosolized in the device, for inhalation by the patient.A suitable drug for use in a pMDI device is salbutamol, which is wellknown for its use for the relief of bronchospasm in conditions such asasthma and COPD.

As discussed above, Corrigan (2011) and Hardwell et al (2011) show thataround 85% of patients fail to use a pMDI correctly. In particular, thismisuse relates to the timing of actuation of the drug canister and theinhalation rate.

Therefore the preferred embodiments of the invention provide anindication to the patient, when using the pMDI device itself, of when toactuate the drug canister, based on the air flow rate through thedevice.

FIGS. 1-3 show various views of an adapter according to an embodiment ofthe first aspect of the invention, in which the adapter is to beattached to a known pMDI device (not shown).

The adapter takes of the form of tube 10 moulded from plastics material.Tube 10 is open at each end 12, 14 and has a substantially constantinternal cross sectional area, unlike known spacer devices. End 12 isfor sealing attachment to an outlet of a known pMDI device. Differentadapters 10 can be manufactured to be specific fits for various knownpMDI devices. End 14 is for the user to place their mouth around andinhale, drawing air through the pMDI device. An air flow rate indicator,in the form of audible indicator 16, is provided in the side wall of thetube 10. In this embodiment, the audible indicator is a reed held at oneend in an aperture in the side wall of tube 10. The reed resonates whena predetermined pressure difference is established across the aperture.Such a pressure difference is established by the patient inhaling. Thus,the predetermined pressure difference can be tuned by suitable selectionof the reed and aperture characteristics so that the reed resonates andproduces an audible signal when the air flow rate through the tube (andthus through the pMDI device) reaches a predetermined level of, e.g. 30liters per minute. This informs that patient that a suitable air flowrate has been produced, so that the patient can activate the drugcanister to deliver the metered dose of drug.

FIGS. 4-6 show various views of a pMDI device 20 according to anembodiment of the fourth aspect of the present invention. Device 20operates in a similar manner to the embodiment of FIGS. 1-3, except thathere the air flow rate indicator 34 is provided integrally with the bodyof the pMDI device.

With reference to FIG. 4, the pMDI device has a plastic body portion 22in an L-shape. The upright of the L-shape is hollow and shaped toreceive drug canister 24. The top end of drug canister 24 stands proudof the end of the body portion 22. At the base of the drug canister isprovided a drug delivery port 26 located in seat 28. Upon depression ofthe canister 24, the drug delivery port is actuated to deliver a metereddose of the liquid drug held in the canister, along with a gaseouspropellant. This mixture is forced through aperture 30 in such a mannerthat an aerosol of the drug is formed.

The user's mouth is received around outlet 32, which forms thetransverse of the L-shape of the plastic body portion 22.

When the user inhales, an air flow is established through the device.Air (shown by arrows A in FIG. 4) is drawn into the device through thegap defined between the canister 24 and the body portion 22. There istherefore a significant constriction along the air flow path. Thereforethe patient inhaling causes a pressure drop in the air flow path.

In a similar manner to that shown in FIGS. 1-3, an air flow rateindicator (in this case an audible indicator) is provided in the deviceof FIGS. 4-6. This audible indicator operates in a similar manner tothat described with reference to FIGS. 1-3. In FIGS. 4-6, the audibleindicator is located in the inlet region of the air flow path. However,this has no deleterious effect on the operation of the device—theaudible indicator is designed in order to generate an audible signalwhen the air flow rate through the device reaches a predetermined level,such as 30 liters per minute.

In use, the patient starts to inhale slowly through the pMDI device. Thepatient gradually increases the rate of inhalation. When the air flowrate reaches the predetermined minimum flow rate, the audible indicatoremits an audible signal (e.g. a constant tone) to the patient, andcontinues to do so even if the air flow rate increases slightly further(e.g. up to about 60 liters per minute). Once the patient hears theaudible signal, the patient actuates the drug canister by depressing it,generating the drug aerosol and inhaling the aerosol via the outlet ofthe device at or near an optimal inhalation rate. In this way, theefficacy of the dose of drug is improved, and preferably maximised. Thisallows the drug to be delivered repeatably and at maximum benefit forthe patient.

FIGS. 7-9 show various views of a pMDI device according to anotherembodiment of the invention. Compared with FIGS. 4-6, the drug canisteris not shown, but it would be present in normal use.

If FIG. 7, the plastic body portion 62 has a similar overall shape tothat shown in FIG. 4. However, there is no audible indicator in thedevice of FIG. 7. Instead, the air flow rate indicator is in the form ofa visual indicator. The visual indicator is a hinged flap 64, located atthe inlet to the air flow path through the device. At the predeterminedair flow rate, the flap changes position, moving against a restoringforce (e.g. gravity, or the restoring force of a spring (not shown)).This indicates to the patient that the minimum air flow rate has beenachieved, and thus the drug canister (not shown) can be actuated todeliver the metered dose of drug.

FIGS. 10-12 show various views of a pMDI device according to a furtherembodiment of the invention. The overall construction of the device issimilar to that shown in FIGS. 4-6, including the location of canister24. However, as shown in FIG. 10, instead of an audible reed or whistle,there is instead provided an air flow rate sensor 80, located justupstream of the outlet of the device. As the skilled person will know,there are various suitable sensors that can be used. For example, a flowrate sensor may operate according to the Venturi effect, with a suitablecombination of pressure sensors and circuitry to relate the pressuredifference due the Venturi effect with the air flow rate through theflow rate sensor. Based on the output of the flow rate sensor 80,suitable circuitry is provided in order to provide an indication to thepatient. For example, indicator arrangement 82 may provide visualindication (e.g. an LED display) and/or audible indication (e.g. asuitable tone or audible instruction).

While the invention has been described in conjunction with the exemplaryembodiments described above, many equivalent modifications andvariations will be apparent to those skilled in the art when given thisdisclosure. Accordingly, the exemplary embodiments of the invention setforth above are considered to be illustrative and not limiting. Variouschanges to the described embodiments may be made without departing fromthe spirit and scope of the invention.

All references referred to above are hereby incorporated by reference.

What is claimed is:
 1. A drug delivery inhaler device having: anL-shaped body with an upright portion for housing a drug reservoir andterminating at an air inlet and a transverse portion terminating at anoutlet for communication with the mouth of a patient; an air flow paththrough the device along which air is drawn from the air inlet of theupright portion of the body to the outlet by inhalation by the patient;a seat for location of a drug reservoir, the drug reservoir beingoperable to deliver a dose of aerosolized drug into the air flow pathfor inhalation by the patient; and an air flow rate indicator operableto continuously indicate when the air flow rate along the air flow pathis at or above a predetermined minimum level suitable for delivery ofthe drug to the patient both before and during delivery of the drug,wherein said air flow indicator is provided integrally with the uprightportion of the body of the device upstream from the point at which thedose of aerosolized drug is ejected into the air flow path.
 2. The drugdelivery inhaler device according to claim 1, wherein the device is oneof: a pressurised metered dose inhaler (pMDI) device, and a dry powderinhaler (DPI) device.
 3. The drug delivery inhaler device according toclaim 1, wherein the predetermined minimum air flow rate through thedevice is at least 30 liters per minute.
 4. The drug delivery inhalerdevice according to claim 1, wherein the air flow rate indicator isadapted to generate an audible or visual signal.
 5. The drug deliveryinhaler device according to claim 1, wherein the air flow rate indicatoris operable electronically.
 6. The drug delivery inhaler device of claim1, wherein the air flow rate indicator comprises a reed configured tooscillate to generate an audible signal.
 7. The drug delivery inhalerdevice of claim 6, wherein the reed is disposed in an aperture in a sidewall of the L-shaped body.
 8. The drug delivery inhaler device of claim1, wherein, in use, the air flow rate indicator is configured to bepositioned upstream of a base of the drug reservoir and downstream of atop end of the drug reservoir in the air flow path.
 9. The drug deliveryinhaler device of claim 1, wherein said air flow rate indicator isadapted to be retrofitted to the drug delivery inhaler device.
 10. Adrug delivery inhaler device having: an L-shaped body with an uprightportion configured for receiving a drug reservoir and terminating at anair inlet and a transverse portion terminating at an outlet forcommunication with the mouth of a patient; an air flow path through thedevice along which air is drawn from the air inlet of the uprightportion of the body to the outlet by inhalation by the patient; and anair flow rate indicator operable to continuously indicate when the airflow rate along the air flow path is at or above a predetermined minimumlevel suitable for delivery of an aerosolized drug to the patient bothbefore and during delivery of the drug, wherein said air flow indicatoris provided integrally with the upright portion of the body of thedevice.
 11. The drug delivery inhaler device according to claim 10,wherein the device is one of: a pressurised metered dose inhaler (pMDI)device, and a dry powder inhaler (DPI) device.
 12. The drug deliveryinhaler device according to claim 10, wherein the predetermined minimumair flow rate through the device is at least 30 liters per minute. 13.The drug delivery inhaler device according to claim 10, wherein the airflow rate indicator is adapted to generate an audible or visual signal.14. The drug delivery inhaler device according to claim 10, wherein theair flow rate indicator is operable electronically.
 15. The drugdelivery inhaler device of claim 10, wherein the air flow rate indicatorcomprises a reed configured to oscillate to generate an audible signal.16. The drug delivery inhaler device of claim 15, wherein the reed isdisposed in an aperture in a side wall of the L-shaped body.
 17. Thedrug delivery inhaler device of claim 10, wherein, in use, the air flowrate indicator is configured to be positioned upstream of a base of thedrug reservoir and downstream of a top end of the drug reservoir in theair flow path.
 18. The drug delivery inhaler device of claim 10, whereinsaid air flow rate indicator is adapted to be retrofitted to the drugdelivery inhaler device.
 19. A drug delivery inhaler device having: anL-shaped body with an upright portion configured for receiving a drugreservoir and terminating at an air inlet and a transverse portionterminating at an outlet for communication with the mouth of a patient;an air flow path through the device along which air is drawn from theair inlet of the upright portion of the body to the outlet by inhalationby the patient; and an air flow rate indicator operable to continuouslyindicate when the air flow rate along the air flow path is at or above apredetermined minimum level suitable for delivery of an aerosolized drugto the patient both before and during delivery of the drug; and said airflow indicator is provided in the air flow path at or proximate the airinlet of the upright portion of the body, wherein said air flow rateindicator is adapted to be retrofitted to the drug inhaler deliverydevice.
 20. A drug delivery inhaler device having: an L-shaped body withan upright portion for housing a drug reservoir and terminating at anair inlet and a transverse portion terminating at an outlet forcommunication with the mouth of a patient; an air flow path through thedevice along which air is drawn from the air inlet of the uprightportion of the body to the outlet by inhalation by the patient; a seatfor location of a drug reservoir, the drug reservoir being operable todeliver a dose of aerosolized drug into the air flow path for inhalationby the patient; and an air flow rate indicator operable to continuouslyindicate when the air flow rate along the air flow path is at or above apredetermined minimum level suitable for delivery of the drug to thepatient both before and during delivery of the drug, wherein said airflow indicator is provided within the upright portion of the body of thedevice, upstream from the point at which the dose of aerosolized drug isejected into the air flow path.